This invention relates to integrated circuit packages, and more particularly to a versatile package to accommodate a family of different large-scale integrated circuits with small variations in connection patterns for different integrated circuits in the family.
Large-scale integrated circuits are commonly mounted in central position on connector boards that include multiple connection pads or finger pads positioned about the periphery of the integrated circuits. Connection pads on the integrated circuit are then conventionally wire bonded or otherwise connected to the finger pads on the connector board that then expands out the area over which multiple connections to the assembly can be formed. Typical connector boards include multiple levels of interconnects between finger pads on one surface (that are wire bonded to connection pads on the integrated circuit), and solder pads on the opposite surface. Each particular configuration of integrated circuit commonly requires a particular configuration of connector board to complete the electrical conductivity from a connection pad on the integrated circuit to a corresponding solder pad on the underside of the connector board. Numerous different integrated circuit types require numerous different connector boards to assure that wire bond connections between connection pads or an integrated circuit and finger pads on the connector board generally correspond in physical arrays to avoid crossing and overlapping wire bonds therebetween by uninsulated wires. In addition, even families of similar integrated circuit types that are distinguished, for example, by processing speeds, or memory capacity, or the like, frequently differ in interconnect patterns only by additional ground (Vss) connections and power (Vdd) connections in addition to signal connections into and out of the integrated circuit. These requirements promote high inventories of connector boards of dedicated designs that frequently differ only in power and ground connections.
Conventional connector boards have been developed which incorporate a ground ring on a connector board disposed about the perimeter of the integrated circuit die. This facilitates making ground connections to connection pads on the die at random locations around the ground ring that avoid overlapping or crossing bond wires. Similarly, power conductors have been positioned on connector boards typically at locations along the sides of the die intermediate, the ground ring and finger pads on the connector board. In this way, power connections can be conveniently made via wire bonds between a connection pad on the die and random locations along the power conductors that avoid overlapping or crossing bond wires. However, such connector boards commonly incorporate specific interconnections between ground ring, power conductors, and the corresponding solder pads with concomitant dedication of the connector board to specific integrated circuit types.
In accordance with the present invention, a connector board of versatile design and layout permits wide variations in interconnect patterns to accommodate a wide variety of different types of integrated circuits mounted thereon. Specifically, undedicated vias or through-connections are provided between solder pads on an underside surface of a connector board and finger pads for wire bond connections to the integrated circuit die mounted on the upper side surface of the connector board. In addition, a plurality of unconnected ground and power conductors are successively spaced about and out from the central mounting region for an integrated circuit die on a connector board. Optional connections of these unconnected or electrically floating conductors to finger pads and associated vias can accommodate multiple patterns of different circuit connections and multiple different voltage supplies associated with different types of integrated circuits.